1. Field of the Invention
This invention relates to a control apparatus for an internal combustion engine.
2. Description of Related Art
A device for detecting abnormalities occurring in an internal combustion engine has been available in the related art. For example, Japanese Patent Application Publication No. 2005-264853 (JP 2005-264853 A) discloses a configuration for identifying a cylinder in which gas leaking from a combustion chamber, and so-called compression loss (leaking of compressed air), occurs. In a normal cylinder, a reaction force created by the compressed air acts during the compression phase, and therefore the speed of rotation of the crank shaft becomes lower as the piston approaches the compression top dead center (TDC). However, since the reaction force is not liable to occur when compression loss occurs in the cylinder, then the amount of reduction in the speed of rotation of the crank shaft when the piston approaches the compression TDC becomes smaller. On the basis of this principle, the determination of compression loss which is disclosed in JP 2005-264853 A is carried out by comparing the amount of reduction in the speed of rotation of the crank shaft, in the compression phase of each cylinder.